Summary

Questions regarding the characteristics of life, with emphasis on nanobacteria, are arranged in sequence for Socratic questioning.

Learning Goals

To understand the definition and uniqueness of life and its complexities

To examine what characteristics constitute a living organism

To recognize the extent of the role nanobacteria play in the movement and molding of life as we perceive it today

To debate the possibility for the existence of life on other planets

Context for Use

This example is suitable for in-class use during a lecture period. No equipment is required unless the instructor wishes to use supplemental images. In that case, the images can be shown either with an overhead or computer projector. This activity is based on the Nanobes and Nanobacteria website, part of the SERC Microbial Life project. Hence, this module may supply images and background information for instructors and students. Excellent general images and other educational resources are available at numerous web sites, such as Microbial Life - Educational Resources, and add significant impact to this topic during class discussions. Some examples are given below in References and Resources.

Description and Teaching Materials

Sample questions arranged in sequence for Socratic questioning regarding whether nanobacteria exist and are alive are listed below. These questions are based on the Nanobes and Nanobacteria website (part of MLER).

What is life? Describe attributes of life that make it distinctive from other parts of the Earth system, such as minerals, water, or light.

What is a nanobacterium? What types of processes are they thought to be responsible for? Why is their existence debatable?

Would you define nanobacteria as living entities? Why or why not? Support your answer with ideas from the previous questions.

If you define a nanobacterium as a living entity, what are the limits of life? Discuss what qualities must be present for something to be considered alive.

If a nanobacterium is not defined as living, what is it?

What molecular pieces are necessary for life? How do nanobacteria pack these molecular pieces into their cell? Might nanobacteria reproduce and replicate cell material in a way that other organisms do not (in a way that is different than our current understanding of these processes)?

How could you experimentally test for the existence of nanobacteria as living organisms? Discuss what methods you would use to determine if nanobacteria are present in a sample.

Teaching Notes and Tips

Tips: Prepare students for the Socratic questioning activity by having them read and take notes on credible sources (e.g. peer-reviewed articles, textbooks, and meeting proceedings- such as The National Academy of Sciences ) regarding the characteristics of life and nanobacteria. Students should use notes from these readings to support their ideas during the activity.

As in all Socratic questioning, give students time to reflect before answering questions, and make an effort to call on different students throughout the class period. Let students know at the beginning of class whether or not you will call on students randomly, or ask for hands to be raised, or both.

To explore questions about the characteristics of life fully, allow at least a full class period of 50 to 90 minutes.

Assessment

During and after this Socratic questioning activity, students should be able to use appropriate terminology and integrate background readings to:

Demonstrate an understanding of the characteristics of life and its complexities

Apply these characteristics to assess if nanobacteria exist, and if so, should be considered living

Recognize the extent of the role nanobacteria play in the movement and molding of life as we perceive it today

Debate whether or not life may exist on other planets and the credibility of evidence for this life

Student responses should be supported by evidence from credible sources such as peer-reviewed journal articles, textbooks, meeting proceedings, etc.

Another measure of success for this Socratic questioning activity is general student feedback-this may include comments made by students regarding the activity itself, if students continue discussing/debating the topic after or outside of class time, or if students contribute to the discussion with their own thoughtful questions (during the activity itself, subsequent class periods, or outside of class).